Saturable Absorber: Transparent Glass-Ceramics Based on Co²⁺, Ga₂O₃-doped ZnO Nanocrystals

A saturable absorber for Er lasers - transparent glass-ceramics with nanosized (6 nm) Co2+, Ga2O3-doped ZnO crystals is developed. It exhibits a broad (4)A(2)(F-4) -> T-4(1)(F-4) absorption band of Co2+ ions in tetrahedral sites. At similar to 1.54 mu m, the saturation intensity is 0.7 +/- 0.1 J/cm(2) and the laser damage threshold is as high as 25 +/- 2 J/cm(2).